ML20084K645

AO 50-265/74-12:on 740612,high Differential Pressure Noted Across Combined High Efficiency & Carbon Filters.Caused by Exhausted High Efficiency Prefilter.Original Carbon Filters, New Rough Prefilters & New Efficiency Prefilters Installed

ML20084K645
Person / Time
Site:	Quad Cities
Issue date:	06/22/1974
From:	Kalivianakis N COMMONWEALTH EDISON CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
AO-50-265-74-12, AO-740622, NJK-74-133, NUDOCS 8305190504
Download: ML20084K645 (3)

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Common th Edison 'v l' C 3 Quad-Citics G:n:ra: ng Stat;on Post Office Box 216 h' W~ M'r #2 Cordova, Illinois 61242 Telephone 309/654-2241 NJK-74-133 June 22, 1974 Mr. John F . O ' Leary , Di rector Directorate of Licensing Regulation U. S. Atomic Energy Commission Washington, D. C. 20545

Reference:

Quad-cities Nuclear Power Station, Docket No. 50-265, DPR-30, Appendix A , Sect ions 1.0.A.4, 4.7.B . I .a( 1) , and 6.6.B. I .a

Dear Mr. O ' Leary:

Enclosed please find Abnormal Occurrence Report No. A0-50-265/74-12 for Quad-Cities NucIcar Power Station. This occurrence was previously re-ported to Region li t , Directorate of Regulatory Operations by telephone on Ju e 13,1974, :nd : legr:r c: Jun  !#! , :.;; :, :nd c 100 to / : ri ::::gr:r on June 14, 1974.

This report is submitted to you in accordance with the requirements of Technical Specification Section 6.6.B.I.a.

Very truly yours, COMM0hWEALTil EDISDN COMPANY QUAD-CITI ES N'JCLEAR POWER STATION p / f

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N . J . Ka l i v ianaki s

Station Superintendent 4 e'I

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h REPORT NUMBER: A0-50-265/74-12 REPORT DATE: June 21,1974 OCCURRENCE DATE: June 12, 1974 FACILITY: Quad-Cities Nuclear Power Station Cordova, Illinois 61242 -

IDENTIFICATION OF OCCURRENCE:

Standby Gas Train "A" High Differential Pressure across the combined high efficiency and charcoal iodine adsorber filters.

CONDITIONS PRIOR TO OCCURRENCE:

1. Both Units Shutdown.

2. Reactor Water Temperature <212 F.

3. No activity being performed which would have reduced shutdown margin.

4 No irradiated fuel being moved.

5. Standby gas train flow controller testing in progress.

DESCRIPTION OF OCCURRENCE:

During routine inspection of the 'A' standby gas train on June 12, 1974,

!! uns discovered thu the system was operating at a lower than rer.:s!

flow as-indicated on the ioccii ilow controller. Wiii i e tening tiie cun-troller, the carbon iodine adsorber filter was observed to have on un-usually high differential pressure resulting in a combined high efficiency filter and charcoal filter differential pressure of 6.8 inches.of water (2.0 inches and 4.8 inches respectively). This exceeded Technical Speci-fication 4.7.B.I.a.(1). The DP gauges were checked for calibration and found to be reading accurately. Differential pressure indication for the demister, rough prefilter, high efficiency prefilter, and high efficiency af ter filter were checked and found to be normal .

On June 14, 1974, the carbon filters were replaced and subsequent train operation Indicated no decrease in carbon filter DP. Further inspection of the instrumentation revealed that the gauge identified as " Carbon todine Adsorber" was actually sensing differential pressure across the high efficiency prefilter, therefore, indicating the high efficiency pre-filter was exhausted and not the carbon filters.

DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:

The high differential pressure across the combined high efficiency and carbon filters was caused by an exhausted high efficiency prefilter.

Imnediate recognition of the cause of the problem was masked by the DP gauge being improperly identified.

ANALYSIS OF OCCURRENCE:

The exhausted high efficiency particulate filter reduced the standby gas' train flow to less than 4000 cfn thus reducing secondary containment C -_ -

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& Q) capability as defined by Technical Specification 3.7.B.3 However, secondary containment integrity was not required by specification 3.7.C.I. Both reactors were subcritical with all rods fully inserted.

The reactor water temperature for both reactors was less than 212 0F.

No activity was being performed which could have reduced the shutdown margin and no irradiated fuel was being moved.

CORRECTIVE ACTION:

The original carbon filters, new rough prefilters, and new high effi-ciency prefilters, were installed on June 15, 1974. Subsequent to filter replacement, the 'A' standby gas train was subjected to DI Octyl-Phthalate (D0P) and " Freon 112" challenge aerosol penetration tests with results of 99.98 and 99.99 per cent leak tight integrity respectively.

Additional operability tests were performed with a train flow of 4000 cfm which consisted of combined differential pressure (3.3 inches water),

differential temperature (20 F), and secondary containment capability tests (0.25 inches water) . These tests demonstrated acceptable filter differential pressure and standby gas train operability.

Additionally, the differential pressure gauges were checked for proper identification and corrected.

FAILURE DATA:

A review of maintenance records revealed no past history of high effi-

.clency pref!!ter rcplaccmcnt. Thc un:.oastcd f! ! tur du..c...tre tcd proper operation of the high efficiency filter to remove particulate contaminants and therefore, no equipment malfunction occurred. As such, this is the first occasion of this type for the standby gas trains and thus there are no safety implications based on cumulative experience.

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